Heat exchange tubing is often used in connection with the production of electrical energy. This tubing often includes a plurality of fins for transferring the heat from a passing fluid in the interior of the tube into another fluid. Often, alloys having tenacious oxide coatings, such as aluminum or titanium, are used to make the tubing materials so that they can be used in corrosive environments, such as those found in gas-to-liquid heat exchangers, hydrogen or air coolers in electrical generators, or interstage coolers and compressors. Because of surface oxides, these corrosion-resistant alloys are very difficult to solder using standard techniques employing lead or tin-based soldering alloys. See for example, Young et al., U.S. Pat. No. 1,970,481, Hertz, U.S. Pat. No. 2,226,243, both of which are hereby incorporated by reference.
Although higher temperature welding techniques are known for their ability to penetrate tenacious oxide coatings, such techniques are inappropriate for relatively thin heat exchange tubing. Accordingly, a need exists for increasing the solderability of readily oxidized heat exchange tubing material, and thus, rendering such materials amenable to conventional soldering techniques.